The present invention relates to a bearing apparatus, and more particularly to a bearing apparatus including a divided rolling bearing and a housing which supports the rolling bearing.
In automotive and marine engines, a bearing for supporting a crankshaft which converts reciprocating motions of pistons into rotary motions thereof is disposed between counterweights or a counterweight and a large end of a connecting rod, and hence, a split bearing is used which is divided into two halves or parts in a circumferential direction.
Although slide bearings have conventionally been used as the supporting bearing, due to recent rising demands for better fuel economy for those engines, it has been proposed to use rolling bearings which are split in a circumferential direction in place of the slide bearings in order to decrease running loss.
The split rolling bearing includes, for example, a pair of split outer ring halves, a plurality of rolling elements or rollers which are provided in such a manner as to roll on respective inner surfaces of the split outer ring halves, and a pair of split cages for holding the respective rollers in such a manner that the rollers are disposed at substantially equal intervals in a circumferential direction. Then, a crankshaft is fitted in the rolling bearing as an inner ring member (for example, refer to JP-A-2006-336765, and JP-A-2006-234134, JP-A-2006-144985).
Further, in the split rolling bearing, while circumferential end surfaces of the pair of split outer ring halves are brought into abutment with each other to form a joint surface, due to an assembling error in assembling the rolling bearing in the housing which has the bearing bore in which the rolling bearing is accommodated or machined conditions of a fitting area of the housing, there may be produced a radial offset between the confronting end portions of the split outer ring halves. As a result, there may be produced a level difference in the joint surface in such a manner as to project radially inwards.
In addition, as is shown in FIG. 9, in the event that a level difference 35 is produced in a radial direction (a vertical direction as viewed in FIG. 9) in a joint surface C between split outer ring halves 33a, 33b, when a roller 34 passes near the joint surface of the outer ring halves where the level difference 35 is being produced, a circumferential surface of the roller collides against an angular edge 35a of the level difference 35, leading to a fear that noise and vibration are generated.
When the roller passes through the level difference, vibration and noise are generated, which is not preferable. To eliminate the effect imposed by the level difference, there have been made various proposals in relation to configurations and sizes of split outer ring halves.
For example, JP-A-2006-336765 proposes that circumferential end portions of outer ring halves are machined to produce inclined surfaces thereof. In addition, JP-A-2006-234134 proposes that a distance from an outer circumferential surface of an inner ring to inner circumferential surfaces of outer ring halves is made larger than an outside diameter of a roller in a position where a joint surface of the outer ring halves exists.
However, the vibration and noise generated when the roller passes through the level difference cannot be sufficiently suppressed with these structures.
Further, in conventional bearing apparatuses including those described in JP-A-2006-336765 and JP-A-2006-234134, however, attention is paid only to a contact between rollers and a level difference, and there has been proposed no conventional bearing apparatus in which attention is paid to a contact between the level difference and circumferential end surfaces of cages. Namely, when rollers roll in association with the rotation of a crankshaft and split cages then start to rotate, circumferential end surfaces of the split cages come into contact with the level difference, whereby vibration and noise may be generated. However, there has been proposed nothing to avoid the contact between the end surfaces of the outer ring halves and the end surfaces of the cages.